A Strategic Crush
by elsarenard
Summary: Mary has become used to being on top of her game at the chess club at her school. However, when a new girl joins the school she is forced to push herself even harder. Though initially infuriated with Eurus Holmes, she soon comes to realize that having someone up to her caliber might not be such a bad thing after all. Mary/Eurus teenlock (high school AU), femslash.


**A/N: Trying a rarepair for fun! Figured Eurus and Mary might match nicely due their high level of intelligence. Also, yes I have no clue if British schools have chess clubs but for the sake of the challenge I'm just going to make it happen. For the record I like Warstan just fine, so I promise it's not ship hating when I write John and Mary as just friends.**

 **Warnings: No sex (check out my smut pieces if you want that). Mentions of Johnlock.**

* * *

Mary had been the reigning champion for years now. To be honest, she didn't even come every week because she found other students were reluctant to join the club if she was too involved. And they needed more members. Desperately.

When she was younger it was all good fun, but it had quickly developed into an ego boost she needed. Seeing how few moves it would take to beat someone else. She'd even gone on to championship matches all over the country. She won those easily enough. There was no denying she was good when it came to the game of chess.

Mary had begun to wonder if new games might be needed to satisfy her. After all, chess wasn't the only thing that took good brain power. Something else at least. A new challenge in her life.

She sighed as she walked into the classroom where the boards were being set up. She glanced around at her fellow students. Anderson was still there for some reason, even though he rarely won. Donovan a few tables away was staring down at a board in rapt concentration. John was chatting with someone else. Mary headed to him first, settling a hand on his shoulder.

"How is everything?" she asked.

"Well enough," John said. "So, who are you going to play with today?"

"Anderson is boring," Mary said. "So probably Donovan if no one else shows up. I've been working on some new strategies anyways… can see how they work on her. What about you, are you just going to watch again?"

"Probably," John said. "You know it's not really my thing." He paused, brow furrowing. "Mary…it's not weird that I keep coming is it? I mean…it made sense when we were dating. But now?"

"It's fine," Mary said.

She smiled at him to let him know she meant it.

The year hadn't been easy. But she thanked her lucky stars that John Watson hadn't completely broken her heart. They'd dated more out of necessity than anything. Drawn together by mutual companionship. However, the chemistry was lacking, which both of them realized. They'd agreed to break it off after a month or so and try seeing other people. Mary was just relieved John had decided they could still be friends. She liked it more like this. Someone she could banter with, get advice from about guys…or girls. The fun of having a fellow bisexual friend.

"Well, if you want we could play," John said. "But I highly doubt that would be much fun for you."

Mary smiled. "No, you're right. I need a challenge. If only there was someone in this school who could really appreciate the art that is chess."

"Yeah," John said with a smirk. "You could use someone to show you a thing or two sometimes. So…weekend plans, because I was thinking I might go see a movie. Want to come with?"

She was about to respond, but fell silent as the door to the classroom opened. And in walked another young woman.

She had long dark hair falling down over her shoulders, pretty facial features, and the most piercing eyes that Mary had ever seen. She cast a cursory glance around the room before settling her gaze on Mary.

"Is this where the chess club meets?" she asked folding her arms.

Mary nodded. "Yes. I'm Mary Morstan. And you are?"

The girl smiled, though it didn't quite reach her eyes. "Eurus Holmes. I'm here to join. See if there's anyone worthy of my talents."

Mary stiffened. "Oh. Is that so? Well I'm happy to play with you, Holmes. If you're interested. I'll warn you I've never lost a match though."

Eurus smiled again, and nodded. She went and sat at the nearest board, carefully keeping her skirt straight as she sat down. She looked up at Mary, tilting her head.

"Show me."

Mary shrugged and came over to sit down as well. She looked down at the white pieces and nodded.

"Well, if you're ready to begin."

"I am," Eurus said.

"Do you usually time it? Write anything down?" Mary asked, settling down in the chair opposite. She looked down at the board, already thinking out her first few moves.

Eurus smiled. "I can keep track of all of it in my head. Now, if you're done stalling."

Mary bristled at the comment and moved her first piece without another word. John had come over to stand at her side, staring down at the board.

Eurus moved her own piece, eyes never leaving Mary's. She smirked as Mary looked over the board again, carefully selecting her next piece to move.

It was easy in Mary's head. Each step led to another. Each action led to a foreseeable consequence, an outcome she almost always could predict. However, to her surprise, Eurus seemed to take actions that she did not expect. She chose moves that seemed nearly random. Mary pursed her lips as one of her pieces was taken out.

It took maybe another five minutes before Eurus spoke again.

"Checkmate," she purred.

Mary looked over the board, eyes going wide. At first she was skeptical. However, with a closer examination she found that Eurus hadn't lied. The pieces had been placed strategically without Mary even realizing it.

"Well played," Mary muttered, though she found she was gritting her teeth.

How could the other girl possibly be so skilled? Never in her life had Mary lost a match. And yet here she was, staring down at the signs of her defeat.

The others around her whispered a bit. She looked up at John and noted that his brow was furrowed, eyes staring at Eurus with clear surprise.

"Well, at least you're willing to admit defeat," Eurus said, tilting her head slightly, a smirk coming over her lips. "I like it when people are willing to realize they've lost."

Mary stood, bumping into the table as she did so, sending chess pieces toppling over. She watched as her queen tumbled down, even as Eurus's remained standing. Perhaps that was appropriate. She'd just been dethroned after all.

"Well, you've won today. You won't be so lucky next time," Mary hissed.

Eurus smiled. "We'll see."

Mary turned and walked to the door, comforting herself by remembering that there was always next week.

* * *

Next week, however, proved much the same. Mary sat down for a rematch with Eurus, watching as the girl tossed back her dark hair and focused her eyes on the chessboard before setting up a cat and mouse game that had Mary losing within a half-an-hour. Eurus smirked and made snotty remarks again, and Mary was forced to realize this wouldn't be quite so simple.

The weeks passed, and with each one Mary would come up with a strategy, only to have Eurus seem to see through it. Within a month Eurus was the new leader of the chess club. Mary was hardly recognized when she came. Anderson and Donovan and several newcomers all flocked to Eurus, asking for advice, wanting to go do things with her on the weekends.

Only John remained somewhat loyal. Until Eurus's cute older brother turned up to pick her up one day.

And then he turned into a blushing mess. Within a few days he wasn't even around all that much anymore.

Mary supposed she couldn't blame him. Sherlock Holmes was rather attractive. However, she had more important things to do at the moment rather than focus on the new boy.

She browsed the internet for more strategies. She watched champion chess matches. She did her best to absorb what information she could. However, Eurus Holmes only seemed to be improving.

There was only one thing left to do. Without another word, Mary left the chess club.

She knew there were other things she could do. Her friend Molly had suggested joining up with a group of students who worked on science projects together. Perhaps something like that would be a nice change of pace. Besides, the rest of the students were now Eurus's little cronies. And John was too caught up in a new whirlwind romance with Sherlock to be of any help.

However, Mary was surprised when a few days later, who should turn up at the science club but Eurus herself.

"What are you doing here?" Mary hissed. "Come to take something else away from me?"

Eurus cocked her head. "I never meant to cause you to quit, Morstan."

"Then why are you here?" Mary asked again.

Eurus sighed and ran a hand through her hair, lips twisting into a frown.

"I just…I miss you at the chess club. It's not nearly so interesting without you there."

"You always beat me," Mary muttered. "Surely it wasn't that interesting."

"No one can beat me at chess," Eurus said. "But you did a fair job of holding me off for a while. You never failed to surprise me, Morstan."

Mary frowned. "What are you saying?"

Eurus tilted her head again, staring at her. Mary just sighed and grabbed for her coat slung over one of the chairs in the classroom.

"Never mind," Mary muttered. "Have fun with the science club, Holmes."

She stalked out into the hallway, slinging her coat on. She felt tears in her eyes as she walked. Brushing them away, she kept walking, determined to go home and think of something else she could do to be better than Eurus Holmes.

"Mary."

She turned just in time to see Eurus there, shoulders slumped, no familiar smirk but a frown instead.

"What do you want?" Mary snapped.

Eurus sighed, eyes closing for a moment before they snapped open. "You know John is dating my brother now, yes?"

Mary shrugged. "So what?"

"I had…initially assumed the two of you were together…you and John," Eurus said. "I… was quite surprised to find that was far from the truth."

"Surprised why?" Mary asked, folding her arms. "What does this have to do with anything?"

Eurus took a deep breath and looked into Mary's eyes.

"Doesn't it occur to you…that everything I've done so far has been to impress you?"

Mary froze. "What?"

"I could have taken it easy on you," Eurus said. "Sometimes I do playing games. Not very fun, to be honest, but it can be entertaining to see the results. However, with you I always had to be on my toes. And I loved that. And I…I admit I liked beating you because it proved I still was better. And because…because…"

Her toe scuffed along the floor as Mary frowned.

"Because I want to impress you," Eurus said again, looking up to meet Mary's gaze. "Because you're the most interesting person in the school. The most interesting I've met if I'm being honest."

"What about me could possibly be interesting to you?" Mary muttered.

"Your skills at chess certainly. And in classes. I've kept an eye on those too. I know you frequent the local shooting range with your father. You are quite good too. And…" Eurus broke off and when she spoke again, it seemed to Mary that the mask on her usually impassive face had slipped away. "And you're quite beautiful on top of all of that."

Mary stared at her for a long moment, trying to understand. Eurus swept another lock of hair out of her eyes. She watched as the other girl's lashes brushed her pale cheeks, head tilting slightly.

"I like you Mary Morstan. Silly as that might be. I do."

Mary felt her heart thump wildly in her chest. After all this time, she'd never imagined that.

Eurus took a step closer, pausing and gazing at her, eyes roving over her face.

Mary bit her lip and nodded slowly. "You're… attracted to me?"

"Quite," Eurus said, a half smile coming onto her face. "And what do you think of that?"

Mary swallowed. "I think… you're not so bad yourself."

She folded her arms again, waiting for Eurus to respond.

"I realize this might be…difficult," Eurus said. "Emotions…usually are. But if you'd be willing, Mary…I'd…be interested in taking you out… or…doing something with you. It's what people usually do isn't it? When they're interested?"

"Yes," Mary said with a small smile. "Yes I suppose they do."

"So… would you like to go do something with me. Maybe…something other than chess?'

Mary smiled. "Yeah, as long as it's not chess…I suppose I would be okay with that."

She hesitated a moment, but it was hard to resist. She reached over and took Eurus's hand. Those fingers that had become so familiar in taking her pieces, wound into hers. She smirked, wondering if for once this meant she'd won. After all, while Eurus might have taken every chess game as the winner, it seemed she might have just won her heart.


End file.
